3. Look at the rims and try and blend the shapes into one another a bit more

4. The seams in the body...you should really be able to see the thickness here it will make a huge difference...there should be a dark line where the split occurs and then a bright highlight right next to it.

5. Put a gravel texture on the road...again not pure black...

As an aside...the flames are interesting...kinda "ghosted", I prefer the more graphic outline look, but these are cool in a different way.